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Technical Paper

UAS Behaviour and Consistency Monitoring System for Countering Cyber Security Threats

2014-09-16
2014-01-2131
Upon their arrival, Unmanned Autonomous Systems (UAS) brought with them many benefits for those involved in a military campaign. They can use such systems to reconnoiter dangerous areas, provide 24-hr aerial security surveillance for force protection purposes or even attack enemy targets all the while avoiding friendly human losses in the process. Unfortunately, these platforms also carry the inherent risk of being built on innately vulnerable cybernetic systems. From software which can be tampered with to either steal data, damage or even outright steal the aircraft, to the data networks used for communications which can be jammed or even eavesdropped on to gain access to sensible information. All this has the potential to turn the benefits of UAS into liabilities and although the last decade has seen great advances in the development of protection and countermeasures against the described threats and beyond the risk still endures.
Journal Article

The Aerodynamics of a Small Car Overtaking a Truck

2014-04-01
2014-01-0604
The influence of a large truck on the aerodynamics of a small passenger car in an overtaking manoeuvre on the motorway was considered, many years ago, during the 1970's, to be a potential problem for the vehicle aerodynamicist. The concern never became significant as vehicle architecture evolved and car weights increased. The current drive for improved fuel economy is advocating that a considerable reduction in vehicle mass is desirable and therefore it may be time to readdress the significance of the truck passing manoeuvre. A quasi-steady experiment has been undertaken at small model scale to examine the aerodynamic characteristics of a small car in proximity to a large truck. Measurements at yaw were included to crudely simulate the effects of a crosswind. The wind tunnel data is presented and the limitations of the experimental procedure are discussed.
Technical Paper

Project Design Studies on Aircraft Employing Natural and Assisted Laminar Flow Technologies

1995-09-01
952038
A multivariate optimisation code has been modified to represent the application of laminar flow to transport aircraft. This has subsequently been used to obtain optimised configurations for conventional and laminar flow designs. Results are presented, demonstrating the economic benefits of introducing laminar flow technologies to subsonic transport aircraft, with passenger payloads in the 107-517 range. These benefits are seen to improve by a factor of between two and three when the designs are optimised to take maximum advantage of the laminar flow. Sensitivity studies were conducted to investigate the impact of the assumptions used within the project studies on the optimum configurations and operating economics.
Technical Paper

Preliminary Investigation of the Influence of a Ground-Plane Boundary Layer on the Aerodynamic Characteristics of Road Vehicle Models Tested Over a Fixed Ground

1996-02-01
960675
Results from a series of experimental measurements are presented in order to investigate the influence of the ground-plane boundary layer on the overall characteristics of a scale model road vehicle. The wind tunnel model is a generic bluff body which has a streamlined forebody, simple wheel representation and interchangeable rear end sections. The aerodynamic forces and moments were measured via an external 3-component balance at a free stream velocity of 24 m/s. corresponding to Reynolds number of 5.5 × 105 based on model length, over a range of ride heights and yaw angles. The ground plane boundary layer thickness was varied artificially. The influence of wheels and underbody roughness were also investigated.
Journal Article

New Slip Control System Considering Actuator Dynamics

2015-04-14
2015-01-0656
A new control strategy for wheel slip control, considering the complete dynamics of the electro-hydraulic brake (EHB) system, is developed and experimentally validated in Cranfield University's HiL system. The control system is based on closed loop shaping Youla-parameterization method. The plant model is linearized about the nominal operating point, a Youla parameter is defined for all stabilizing feedback controller and control performance is achieved by employing closed loop shaping technique. The stability and performance of the controller are investigated in frequency and time domain, and verified by experiments using real EHB smart actuator fitted into the HiL system with driver in the loop.
Technical Paper

Millimetre-Wave Automotive Radar Advance Path Measurement

2002-03-04
2002-01-0820
Millimetre wave radar sensors are being actively developed for automotive applications including Intelligent Cruise Control (ICC), Collision Warning (CW), and Collision Avoidance (CA). Knowledge of the road geometry is of fundamental importance to these future intelligent automotive systems. The interest in such systems is evidenced by manufacturers now starting to incorporate radars in production luxury vehicles. Determination of the road geometry, day and night, under all weather conditions, is a challenging problem requiring both fundamental research and systems studies. Current automotive radar systems rely heavily on the use of extrapolating yaw rate data generated within the vehicle to produce a prediction of the path of the road ahead. This use of historical data is only satisfactory if the road trajectory is uniform. Sudden discontinuities in the path, such as bends, cause this method of path prediction to produce significant errors.
Technical Paper

Comparing Static and Dynamic Testing Techniques for the Crosswind Sensitivity of Road Vehicles

1996-02-01
960674
An accurate simulation of a ground vehicle interacting with a crosswind gust can be achieved by using a moving model mounted on a track such that it can traverse the working section of a conventional atmospheric boundary layer wind tunnel. This paper will briefly describe the facility that is being developed at Cranfield University and detail comparisons between static and dynamic data from tests on three basic model configurations. Under the same nominal wind input, data from static tests compares well with that from dynamic tests at yaw angles below 15°. At higher yaw angles, after the onset of “large scale” separation, the dynamic values of the forces and moments become larger than the static values.
Technical Paper

CRISTO: A Code for Integrated Synthesis and Trajectory Optimization of Commuter and Regional Aircraft

1997-10-01
975542
This paper describes a computer code for conceptual design of mission optimized twin-turboprop Commuter or Regional aircraft. Optimum configurations and flight profiles of such aircraft are determined by coupling this code to an optimization code based on Simulated Annealing. As an example, minimum DOC configurations were determined for 50-seat Regional aircraft for operation over three stage lengths. The DOC per seat-nm and DOC per trip of the optimum aircraft were found to be comparable or significantly (8 to 17 %) lower than the corresponding values for five contemporary 40 to 50 seater aircraft for short stage lengths.
Technical Paper

Assessing the Effects of Shear and Turbulence During the Dynamic Testing of the Crosswind Sensitivity of Road Vehicles

1997-02-24
970135
With increasing speeds and the anticipated reduction in weight of modern cars, the issue of crosswind sensitivity is becoming increasingly important. In a previous paper by the same authors, the normal method of testing such aerodynamic characteristics at model scale, using static models at yaw to the freestream, was compared with dynamic testing, in which the model is propelled across a ‘gust’ simulated by a wind tunnel. A direct comparison using a similar gust profile for both static and dynamic tests was made with the conclusion that the simple static test technique was underestimating the true transient loads. Further tests have been carried out, on a generic squareback (or estate) model, during which the effect of varying both the vertical velocity profile and the turbulence intensity within the gust was considered.
Technical Paper

A Part-Time Master's Course Incorporating Aircraft Design, Build and Flight Test

1997-10-01
975575
The successful completion of aerospace projects usually involves the bringing together of many different specialist skills. The need for the engineer to become multidisciplined is today's reality, but this is becoming increasingly harder to achieve naturally in the working place. Recent industrial drives towards concurrent engineering have revealed a need for just this type of engineer. The 3 year part-time MSc course in Aircraft Engineering was designed to address these needs and was launched with the first intakes of delegates in 1995. The course is modular and students are encouraged to “mix” disciplines, combining topics such as avionics and structural analysis. The course has created skilled specialists and engineering leaders for the future, with improved technical ability and career potential, albeit at the cost of hard work! The course consists of 3 elements, namely:- Lecture courses held in one-week blocks, over the 3 year period. An individual piece of research.
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